Flying in Flurries

darthnomster

darthnomster

Pre-takeoff checklist
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Looking for opinions. VFR pilot with about 90hrs. Flying a 172R in southwest Ohio.

I generally spend at least part of my drive to work thinking "would I fly right now?". The rule that I recall from PPL training was, OAT at or below freezing + visible moisture = icing.

How much snow do I need before deciding to scrub a flight? I'm looking at a snow density of one snowflake per cubic meter right now out my office window. I'm talking very light flurries here. What think you?

I'll call and ask my club CFI later today to get his opinion, but wanted to hear from some others.
 
I've been in the air when I encountered flurries. I was probably 3k ft below the ceiling and 20 minutes from my destination. The fluries were a surprise (not forcast) but didn't affect visability and I just went on until they stopped about 10 miutes later.
 
Visibility is visibility. Snow doesn't bother me as long as I can see for as far as I'm required to see.
 
If you have visibility, you can fly in snow. Its possible to get icing though I never have. Go ahead and try it, stay in the pattern. If it works out, venture to the nearest airport. Don't fly into a cloud. If you see a cloud coming and cant go down comfortably, turn around and go back. Snow is interesting.
 
Flurries sometimes look innocent on the ground. But when you are up in the air you can lose visibility very easily. Not something I would gamble with as a VFR only pilot.
 
If they start while airborne and they are light (like flurries), no problem.
To avoid icing (any precip) stay at least 2-digit temperature differentials (*C up or down) from freezing temps.
If on the ground, probably think twice, especially if low on experience and have your aircraft deiced (chemically) before attempting take-off
 
I'd say if visibility is within limits, and the OAT is a few degrees below freezing up through your intended cruise altitude, go for it. Just be aware that visibility can change rapidly if the snow starts falling quickly. I probably wouldn't be planning a long XC through snow the whole way, but nothing wrong with making some short hops if the forecast supports it.
 
darthnomster said:
Looking for opinions. VFR pilot with about 90hrs. Flying a 172R in southwest Ohio.

I generally spend at least part of my drive to work thinking "would I fly right now?". The rule that I recall from PPL training was, OAT at or below freezing + visible moisture = icing.

How much snow do I need before deciding to scrub a flight? I'm looking at a snow density of one snowflake per cubic meter right now out my office window. I'm talking very light flurries here. What think you?

I'll call and ask my club CFI later today to get his opinion, but wanted to hear from some others.
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My concern with you in flurries is not so much one of icing since the water is already frozen. My concern is more one of getting into inadvertent IMC. If the ceilings are reasonable, just stick close to home. Pattern work you're fine.
 
I flew through some snow the other day that was not forecast. I was very cautious as the temp was fluctuating between +1c to -2c. I was not very comfortable with it, and kept thinking it could all change to icing at any moment. I flew around as many of the visible snow areas as possible and always kept an out towards clear weather on one side. I wouldn't do it unless it was unexpected and you have an out.
 
Along with visibility requirements watch out for mixed rain and snow - that may ruin your whole day. If it's just a little shower (you can see through it and enough around it to know it's small) of mixed rain/snow and you can get through it in 30 or 60 seconds then you won't accumulate enough ice to matter.

I'm pointing this out because I've been in a situation where there were snow showers around and then I found the mixed precip just off the end of the runway at my destination.

On the other end of the scale was a trip from Lubbock to Denver and about half was in snow. ATC was real interested in icing reports but I just had to tell them "negative icing" - It was about 20* F on departure at Lubbock so I wasn't real concerned with ice with the arctic airmass - now if the moisture had been from the gulf the story might have been different. Anyway, pay a little attention to the big picture and a lot of attention to the view out the window....and get your instrument rating as soon as possible.
 
oldShar said:
If they start while airborne and they are light (like flurries), no problem.
To avoid icing (any precip) stay at least 2-digit temperature differentials (*C up or down) from freezing temps.
If on the ground, probably think twice, especially if low on experience and have your aircraft deiced (chemically) before attempting take-off
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This statement really intrigues me. I really don't want to hijack the thread, but think it is on topic.

I've been struggling as an IFR pilot with the Go/No-go decision when it comes to icing. I am personally comfortable with many conditions, but I don't want to turn myself into a streaking ice cube with streaking underwear, nor do I want to test the waters in an uneducated way. So far, I've been leaning towards the first option listed below.

Here is the mixed information that I've heard:

- In IFR checkride prep, I was pretty much told to stay VFR and completely out of "visible moisture" (ie., clouds). "You will ice up immediately and die!" Pretty much the message I got was comparable to the high school girl being told swimming with boys will get you pregnant.

- At one point, though, my flight instructor told me that there is a temperature range that you should be OK with. If remember correctly, it was below around 15*F and you're OK, but between 15-33*F is the danger zone. This sounds similar to what you're saying, but if yours is -10*C-+10*C, that is like 50*F which seems pretty darn warm to me.

- I had a different instructor tell me at one point that as long as it is snowing, you'll be OK. That the moisture droplets are too big to stick to the plane?

- I watched a great FAA educational video on YouTube which stated that trace icing buildup time is like an inch per hour, light icing is like an inch in 45 minutes, moderate was something like 15-45 minutes, and severe icing was less than 15 minutes. My conclusion is that if the layer is only about 2000'-3000' thick, I'd only be in it for maybe 2-5 minutes, so flying up through a layer like that in trace or light icing would really not be much of a factor.

- Another high-hour pilot buddy of mine told me that his method is to look at pireps, and if there are none or negative reports, he will go. He does not use the ADDS icing products... Thinks they're overly cautious. That really surprised me... but the guy has been flying in the snow belt for 30+ years on a weekly basis in a non-FIKI plane.

So, since everyone has a differing go/no-go decision, how do you make your decisions? I'm getting a lot of mixed messages here.

-Andrew
 
I flew in light snow once during my training. Visibility was terrible (first time I'd flown in such low visibility conditions) and I won't lie it kinda freaked me out. I was barely able to see the airport from the pattern. But I was the one who decided to go up for a couple takeoffs/landings when my CFI said we were still ok to go.

Worse than the visibility was the wind and the runway. At the time my landings were still very rough at times and then you add in a crosswind and a runway with blowing snow and it wasn't pretty. This was also on the shorter of the two runways at my airport which I had not used in months. The first landing was barely passable, and the second one my CFI had to help once we touched down because we landed a little long and couldn't stand on the brakes very hard because of the snow on the runway. After that I called it and we went back inside.

Was I nervous/scared during those two trips around the pattern? Yes, even though I had a CFI in the right seat, I knew it was still my responsibility to get us on the ground. Am I glad we went up that day? Very much so. I know that weather like that is like in the air and know that for the time being, I'm going to do my best to avoid it. But I also know I can handle it as long as I'm cautious and do everything I was taught.
 
There is a wildcard in the 'low enough temp and you are safe' clause though, and that is SCLD, or Super Cooled Liquid Droplet, phenomenon. It's not highly common and I'm not making a panic call about it, just pointing out that it is a factor to look at regardless the temps.

Liquid water can exist in a supercooled form in clouds that basically instantly freezes to you as you disturb it. This is what brought down the ATR-72 in Rose**** Illinois, if you google that, you will find much good information.

Another good resource you should understand if you are going to be flying winter IFR is the Skew-T data. This is probably the best resource for predicting icing on a flight that one has. Unfortunately Scott who teaches the subject well is no longer a resource on this board, however a bit of Google-Fu should get you his website.
 
Henning said:
There is a wildcard in the 'low enough temp and you are safe' clause though, and that is SCLD, or Super Cooled Liquid Droplet, phenomenon. It's not highly common and I'm not making a panic call about it, just pointing out that it is a factor to look at regardless the temps.

Liquid water can exist in a supercooled form in clouds that basically instantly freezes to you as you disturb it. This is what brought down the ATR-72 in Rose**** Illinois, if you google that, you will find much good information.

Another good resource you should understand if you are going to be flying winter IFR is the Skew-T data. This is probably the best resource for predicting icing on a flight that one has. Unfortunately Scott who teaches the subject well is no longer a resource on this board, however a bit of Google-Fu should get you his website.
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Thanks, Henning, for the SLD tip. That is a good point. But, that aside, I am still unsure of where others' limits are.

I have studied SKEW-T data. My interpretation is that it is a resource for better predicting cloud levels and layers.

That is all good, but my question really relates more towards the go/no-go decision. If you see a 3000' layer, no SLD, and it's about 25*F through that layer, would you go through it?
 
ahkahn said:
Thanks, Henning, for the SLD tip. That is a good point. But, that aside, I am still unsure of where others' limits are.

I have studied SKEW-T data. My interpretation is that it is a resource for better predicting cloud levels and layers.

That is all good, but my question really relates more towards the go/no-go decision. If you see a 3000' layer, no SLD, and it's about 25*F through that layer, would you go through it?
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My personal limits without deicing gear on the plane is zero. I do not do freezing IMC. I have hauled ice by accident and had pretty much resigned to dying in it, and a couple times on pipeline patrol I pushed through it in ground effect and hopping off frozen pastures, but no, I live in Florida for a reason, I don't like ice.;) I rarely fly IMC anyway because the reason I spend the money to fly myself is the view, and IMC screws that up. I feel better close to the ground and under the clouds, plus the view of the country going by at 100' @ 165kts is pretty sweet.

Would I pop up through a layer I have no reason to think it will ice me? Sure, no worries. If I know the parameters are good, the question of icing is moot.
 
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Henning said:
Would I pop up through a layer I have no reason to think it will ice me? Sure, no worries. If I know the parameters are good, the question of icing is moot.
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I think that circles back to my original question. Under what conditions do you (or others) consider icing to be a potential factor?
 
ahkahn said:
I think that circles back to my original question. Under what conditions do you (or others) consider icing to be a potential factor?
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:lol: Here we pop back to the answer, "It depends". I'm not mocking you, in fact the opposite. I face the same dilemma every time I am posed with the question, so I completely empathize with your frustration in the answers not providing clarity. There are so many different factors involved that pointing to one is impossible.

What I tried to convey in my last post is that I approach the scene with a 'no go' and then have to asses my way into a 'go'. IOW I look for things that are likely to kill me, and if I don't find them, I go, maybe, if I can't get out underneath.
 
This really is a tough question to answer and is a big part of why GA slows down in the winter.
 
JasonM said:
That would be pretty sweet. Would that even be possible though? crossing the country at 100' agl?
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Oh yes, quite easy in fact if you know the pipeline routes. Actually anymore with moving map GPS, it's simple. Flying pipeline I would only get above 100' when I was at the top of hard turns maneuvering in collection fields.
 
Sometimes you never know until you get in the air. I've flown in snow that combined with the speed of the plane came pretty darn close to IFR conditions.
 
AdamZ said:
Sometimes you never know until you get in the air. I've flown in snow that combined with the speed of the plane came pretty darn close to IFR conditions.
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Me too, VFR in snow flurries, mooney 201, just south of bradford, penna. But.......they became worse and I barely made it into Scranton , pa. Flying in the sandwich, could not go up, or down. Dumb dumb decision! If you experience this once you will not ask this question again! ( if you survive.)
 
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One mile visibility in snow at 500' AGL is not fun. I don't care what anyone else says about that. The one consolation is that with skis installed there are lots of landing opportunities if the weather gets worse.

To the guys who asked about go/no-go? In snow it's difficult to estimate the ceiling or what a reasonable flight ceiling might be unless you have some landmarks to assist in that decision like hills, mountains, etc. My cabin sits about 2 miles from the foot of a mountain and in winter it's obscured much of the time but that doesn't mean the ceilings are too low to fly. I'm forced to look around for other clues. All I need is a couple hundred feet above the trees for me to take off. That allows me a safe turn around if I don't like what I see once I get up. If the visibility is adequate once up? Off I go. If I'm in town and the weather's 1000' and 3 or better? I won't hesitate to request a Special VFR departure if I think the weather's similar away from the airport. If I was in unfamiliar surroundings in a place where I didn't know the weather patterns and didn't have skis? My minimums would change. If I'm not feeling well? My minimums change. Any discussion of go/no-go needs to be taken with a grain of salt. No two pilots are the same, no two flights are the same.

The best advice I ever got from a seasoned bush pilot- When flying weather rarely catches you from behind. In almost all cases you'll fly into it. There's nothing wrong with poking your nose into the weather as long as you don't let the door close behind you.
 
If it's cold enough it's more a visibility issue than a ice issue.

Would I go VFR, sure, but I'm also flying a /G and can pull a IFR if needed.

If it's just some sporadic -SN go for it but keep it local.
 
My personal policy... Snow is not an issue below 25f as it just blows off the surface of the plane... 26f -38f.. I DON'T fly... cause it sticks... Sometimes ALOT..


YMMV...
 
ahkahn said:
I think that circles back to my original question. Under what conditions do you (or others) consider icing to be a potential factor?
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I've got two answers -

1) If you aren't flying into a situation where you'd have an accident and people (we) would say "WTH was he thinking?"
2) I believe it was the NM/PA-28 thread that someone pointed out that the airlines use visible moisture combined temps below +5C to deem that icing is likely. Seems like a good limit to me. I'm sure there are people who will push for a softer limit than that. In fact I know there are because we read about their icing accidents all the time.

Works for me. YMMV.
 
Honestly, I'm more concerned by freezing rain than I am snow since it's wetter and sticks to the airplane in a hurry. I got a fair amount of clear ice in good VFR conditions once by flying into a random rain shower while deviating around some other precipitation with the temperature aloft right at freezing.
 
So, here's my opinion based on my military flying experience and getting ready to jump back into GA when I retire.

1. Unless you're being paid to do it and have the equipment (and experience) err on the side of caution. You don't have to take off, but you damn sure have to get it back on the ground safely.

2. If you're not being paid to do it, the price you pay is your life.

3. If you haven't done it before, you should probably find the right CFI and experience it in a learning environment. Instrument flying capability does not equal winter weather experience.



Sent from my iPad using Tapatalk
 
VFR flight in snow has been done since airplanes were invented. There's nothing inherently dangerous about it. Stay VFR and enjoy it. Winter flying is a bit of a chore (pre-heat, wing covers) but it's very satisfying. And with days getting longer it's getting a little easier to pull off.
 
GCA319 said:
Honestly, I'm more concerned by freezing rain than I am snow since it's wetter and sticks to the airplane in a hurry. I got a fair amount of clear ice in good VFR conditions once by flying into a random rain shower while deviating around some other precipitation with the temperature aloft right at freezing.
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Freezing rain is the biggest worry when there is an inversion above you and you are at freezing or below - and yes, freezing rain can (and has) killed many people. With that being said, if you are in the inversion (above freezing) you are generally alright.
 
I just flew through a pop up snow event last time I flew last week. The key to me feeling safe was I knew I had an out. I kept several airports within a few mile of me wherever possible and I knew the weather was ok apart from the pop up snow.

I got about 6 miles from the airport and still could not see it so visibility was certainly reduced. The sky looked dark up ahead so I simply 180'd my way out of there and flew to clear sky's. I never worried about icing because the stuff falling outside is already frozen and that, at least in my understanding, means that accumulating ice on the surfaces is much tougher than if the stuff falling is liquid and then freezes.

When I was safe and clear of the precipitation I gave ATC a buzz and made a pilot report because literally nothing was forecast about snow during my pre-flight weather briefing. I gave ATC a heads up about the conditions and they asked other pilots in the area if they were experiencing similar conditions. I felt like I wante to help my fellow pilots out and give them a heads up about what they were flying into.

It was a bit tense for a few minutes but I kind of expect winter weather flying to be a challenge!
 
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Stewartb said:
Winter flying is a bit of a chore (pre-heat, wing covers) but it's very satisfying. .
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{{ you forgot about "...(pre-heat, wing covers, gasoline running down your arm while sumping)..." }} [[Capt Murphy says!!]] :)
 
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